Sliding compound miter saws comprise a motor unit pivotally mounted on a base. The motor unit is located above the base and can pivot between a high position where it is located furthermost away from the base to a low position where a circular saw blade, which is mounted on the motor unit and which is capable of being rotationally driven by a motor located within the motor unit, can engage with a work piece located on the base. A spring biases the motor unit to its uppermost position.
Such saws have a sliding feature wherein the motor unit, in addition to be able to perform a pivotal or chopping movement, can slide linearly across the base to perform a slide cut. Furthermore, these types of saw include mechanisms by which they are able to perform miter and bevel cuts on work pieces located on the base.
These types of saw comprise guards which surround the edge of the saw blade in order to prevent the operator from touching the cutting edge. Typically, such saws comprise a fixed guard which surrounds the cutting edge of the top half of the cutting blade and a pivotal guard which is capable of surrounding the cutting edge of the lower half of the cutting blade. The pivotal guard is capable of being pivoted from a first position where it surrounds the cutting edge of the lower half of the cutting blade to a retracted position where the cutting edge of the lower half of the cutting blade is exposed so that the cutting blade can be used to cut a work piece. The purpose of the pivotal guard is to enable the cutting edge of the lower half of the circular saw blade to be surrounded when the saw blade is not being used to provide protection to the operator while allowing the cutting edge of the lower half of the circular saw blade to be exposed when it is required to perform the cutting function.
EP1772221 describes one example of a sliding compound miter saw.
Referring to FIG. 1, the saw described in EP177221 comprises a base 2 in which is mounted a circular table 4. The circular table 4 can rotate about a vertical axis. An arm 6 is attached to the front of the circular table 4 which extends through a recess 8 formed in the front of the base 2 and then forward of the base 2. As the circular table rotates, the arm 6 swings within the recess 8, the maximum amount of pivotal movement being limited by the sides 10 of the recess 8. A latch 12 is attached to the underside of the end of the arm 6 which is capable of releasably locking the angular position of the arm 6 within the recess 8. A fence 14 is rigidly attached to the base 2 and passes over the circular table 4.
Pivotally attached to the rear of the circular table 4 is a bevel support 16. The bevel support 16 can pivot about a horizontal bevel axis 18. The bevel support 16 can be locked in a range of angular positions relative to the circular table 4 using a locking handle 20.
Pivotally mounted onto the bevel support 16 is a slide support 22. The slide support 22 can pivot about a chopping axis 24 which is parallel to the axis of rotation 26 of a cutting blade 28.
Rigidly mounted within the slide support 22 are the ends of two straight rods 30; 32. The rods 30; 32 are prevented from sliding or rotating within the slide support 22. The rods 30, 32 are located one above the other and are parallel to each other. Attached to the end 34 of the top rod 30 is a spring 36. The other end of the spring 36 is attached to the bevel support 16. The spring 36 is under tension, biasing the end 34 of the top rod 30 downwardly, biasing the ends of the two rods 30, 32 located remotely from the slide support 22 upwardly due to the pivotal connection of the slide support 22 to the bevel support 16.
Slideably mounted onto the two rods 30, 32 is a saw assembly 38. The saw assembly 38 comprises a motor housing 40 in which is mounted an electric motor. The electric motor is powered via an electric cable 42. Mounted on the front of the motor housing 40 is a handle 44. A trigger switch 46 is mounted within the handle 44, which when depressed, activates the motor. A drive spindle 48 projects from the housing 40. A circular saw blade 28 is rigidly mounted onto the drive spindle 48. When the motor, is activated, the drive spindle rotates, rotatingly driving the saw blade 28. A fixed guard 52 is rigidly mounted onto the motor housing 40 and surrounds the top cutting edge of the saw blade 28. A pivotal guard 54 is pivotally mounted on the motor housing 40 and can pivot about the axis of rotation 26 of the saw blade 28. The pivotal guard 54 can pivot between an enclosed position where it surrounds the lower cutting edge of the saw blade 28 and a retracted position where it exposes the lower cutting edge of the saw blade 28. When the pivotal guard is in the retracted position, it is telescopically pivoted into the fixed guard 52. A pivotal guard spring biases the pivotal guard 54 to the enclosed position.
The saw assembly 38 can slide along the two rods 30, 32 towards or away from the slide support 22.
In use, a work piece is placed on the base 2 and circular table 4 against the fence 14. The pivotal movement of the circular table 4 about the vertical axis allows the saw to perform miter cuts on the work piece. The pivotal movement of the bevel support 16 in relation to the circular table 4 about the bevel axis 18 allows the saw to perform bevel cuts on the work piece. The pivotal movement of the slide support 22 on the bevel support 16 about the chopping axis 24 allows the saw to perform chop cuts on the work piece. The sliding movement of the saw assembly 38 along the two rods 30, 32 allows the saw to perform sliding cuts on the work piece.
The saw comprises a pivotal guard actuating mechanism. The pivotal guard actuating mechanism causes the pivotal guard to pivot to its retracted position when the saw assembly is pivoted about the chopping axis 24 from its upper position to its lower position. The spring 36 biases the saw assembly 38 to pivot about the chopping axis 24 to its uppermost position. In this position, the pivotal guard 54 encloses the lower edge of the cutting blade 28. As the saw assembly is pivoted downwardly towards the circular table 4, the pivotal guard actuating mechanism causes the guard 54 to retract into the fixed guard 52, exposing the lower cutting edge of the blade 28.